Reactions of 2-, 6-, and 8-monosubstituted 1- and 3-methylpurines with hydroxide ions in water

Abstract

The reactions of 2-, 6-, and 8-monochloro-(or methylthio-)1-(and 3-)methylpurines towards N-sodium hydroxide have been examined. 1-Methyl-2- and -6-methylthiopurine underwent normal nucleophilic displacement to give the hydroxypurines, but 1-methyl-8-methylthiopurine underwent ring fission to give 5-amino-2-methylthioimid-azole-4-carbaldehyde. 3-Methyl-6-methylthiopurine afforded 5-methylaminoimidazole-4-carbaldehyde predominantly, and some 6-hydroxy-3-methylpurine; and 3-methyl-8-methylthiopurine underwent ring opening like its 1-methyl isomer. 7-(and 9-)Methyl-2-methylthiopurines (for comparison) gave 4-amino-5-methyl-amino- and 5-amino-4-methylamino-2-methylthiopyrimidines, respectively. 6-Chloro-3-methylpurine gave 5-methylaminomidazole-4-carbonitrile and some 6-hydroxy-3-methylpurine; but 8-chloro-3-methylpurine was consumed without forming 8-hydroxy-3-methylpurine.